/** * @fileoverview enforce consistent line breaks inside function parentheses * @author Teddy Katz * @deprecated in ESLint v8.53.0 */ "use strict"; //------------------------------------------------------------------------------ // Requirements //------------------------------------------------------------------------------ const astUtils = require("./utils/ast-utils"); //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ /** @type {import('../types').Rule.RuleModule} */ module.exports = { meta: { deprecated: { message: "Formatting rules are being moved out of ESLint core.", url: "https://eslint.org/blog/2023/10/deprecating-formatting-rules/", deprecatedSince: "8.53.0", availableUntil: "10.0.0", replacedBy: [ { message: "ESLint Stylistic now maintains deprecated stylistic core rules.", url: "https://eslint.style/guide/migration", plugin: { name: "@stylistic/eslint-plugin-js", url: "https://eslint.style/packages/js", }, rule: { name: "function-paren-newline", url: "https://eslint.style/rules/js/function-paren-newline", }, }, ], }, type: "layout", docs: { description: "Enforce consistent line breaks inside function parentheses", recommended: false, url: "https://eslint.org/docs/latest/rules/function-paren-newline", }, fixable: "whitespace", schema: [ { oneOf: [ { enum: [ "always", "never", "consistent", "multiline", "multiline-arguments", ], }, { type: "object", properties: { minItems: { type: "integer", minimum: 0, }, }, additionalProperties: false, }, ], }, ], messages: { expectedBefore: "Expected newline before ')'.", expectedAfter: "Expected newline after '('.", expectedBetween: "Expected newline between arguments/params.", unexpectedBefore: "Unexpected newline before ')'.", unexpectedAfter: "Unexpected newline after '('.", }, }, create(context) { const sourceCode = context.sourceCode; const rawOption = context.options[0] || "multiline"; const multilineOption = rawOption === "multiline"; const multilineArgumentsOption = rawOption === "multiline-arguments"; const consistentOption = rawOption === "consistent"; let minItems; if (typeof rawOption === "object") { minItems = rawOption.minItems; } else if (rawOption === "always") { minItems = 0; } else if (rawOption === "never") { minItems = Infinity; } else { minItems = null; } //---------------------------------------------------------------------- // Helpers //---------------------------------------------------------------------- /** * Determines whether there should be newlines inside function parens * @param {ASTNode[]} elements The arguments or parameters in the list * @param {boolean} hasLeftNewline `true` if the left paren has a newline in the current code. * @returns {boolean} `true` if there should be newlines inside the function parens */ function shouldHaveNewlines(elements, hasLeftNewline) { if (multilineArgumentsOption && elements.length === 1) { return hasLeftNewline; } if (multilineOption || multilineArgumentsOption) { return elements.some( (element, index) => index !== elements.length - 1 && element.loc.end.line !== elements[index + 1].loc.start.line, ); } if (consistentOption) { return hasLeftNewline; } return elements.length >= minItems; } /** * Validates parens * @param {Object} parens An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token * @param {ASTNode[]} elements The arguments or parameters in the list * @returns {void} */ function validateParens(parens, elements) { const leftParen = parens.leftParen; const rightParen = parens.rightParen; const tokenAfterLeftParen = sourceCode.getTokenAfter(leftParen); const tokenBeforeRightParen = sourceCode.getTokenBefore(rightParen); const hasLeftNewline = !astUtils.isTokenOnSameLine( leftParen, tokenAfterLeftParen, ); const hasRightNewline = !astUtils.isTokenOnSameLine( tokenBeforeRightParen, rightParen, ); const needsNewlines = shouldHaveNewlines(elements, hasLeftNewline); if (hasLeftNewline && !needsNewlines) { context.report({ node: leftParen, messageId: "unexpectedAfter", fix(fixer) { return sourceCode .getText() .slice( leftParen.range[1], tokenAfterLeftParen.range[0], ) .trim() ? // If there is a comment between the ( and the first element, don't do a fix. null : fixer.removeRange([ leftParen.range[1], tokenAfterLeftParen.range[0], ]); }, }); } else if (!hasLeftNewline && needsNewlines) { context.report({ node: leftParen, messageId: "expectedAfter", fix: fixer => fixer.insertTextAfter(leftParen, "\n"), }); } if (hasRightNewline && !needsNewlines) { context.report({ node: rightParen, messageId: "unexpectedBefore", fix(fixer) { return sourceCode .getText() .slice( tokenBeforeRightParen.range[1], rightParen.range[0], ) .trim() ? // If there is a comment between the last element and the ), don't do a fix. null : fixer.removeRange([ tokenBeforeRightParen.range[1], rightParen.range[0], ]); }, }); } else if (!hasRightNewline && needsNewlines) { context.report({ node: rightParen, messageId: "expectedBefore", fix: fixer => fixer.insertTextBefore(rightParen, "\n"), }); } } /** * Validates a list of arguments or parameters * @param {Object} parens An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token * @param {ASTNode[]} elements The arguments or parameters in the list * @returns {void} */ function validateArguments(parens, elements) { const leftParen = parens.leftParen; const tokenAfterLeftParen = sourceCode.getTokenAfter(leftParen); const hasLeftNewline = !astUtils.isTokenOnSameLine( leftParen, tokenAfterLeftParen, ); const needsNewlines = shouldHaveNewlines(elements, hasLeftNewline); for (let i = 0; i <= elements.length - 2; i++) { const currentElement = elements[i]; const nextElement = elements[i + 1]; const hasNewLine = currentElement.loc.end.line !== nextElement.loc.start.line; if (!hasNewLine && needsNewlines) { context.report({ node: currentElement, messageId: "expectedBetween", fix: fixer => fixer.insertTextBefore(nextElement, "\n"), }); } } } /** * Gets the left paren and right paren tokens of a node. * @param {ASTNode} node The node with parens * @throws {TypeError} Unexpected node type. * @returns {Object} An object with keys `leftParen` for the left paren token, and `rightParen` for the right paren token. * Can also return `null` if an expression has no parens (e.g. a NewExpression with no arguments, or an ArrowFunctionExpression * with a single parameter) */ function getParenTokens(node) { switch (node.type) { case "NewExpression": if ( !node.arguments.length && !( astUtils.isOpeningParenToken( sourceCode.getLastToken(node, { skip: 1 }), ) && astUtils.isClosingParenToken( sourceCode.getLastToken(node), ) && node.callee.range[1] < node.range[1] ) ) { // If the NewExpression does not have parens (e.g. `new Foo`), return null. return null; } // falls through case "CallExpression": return { leftParen: sourceCode.getTokenAfter( node.callee, astUtils.isOpeningParenToken, ), rightParen: sourceCode.getLastToken(node), }; case "FunctionDeclaration": case "FunctionExpression": { const leftParen = sourceCode.getFirstToken( node, astUtils.isOpeningParenToken, ); const rightParen = node.params.length ? sourceCode.getTokenAfter( node.params.at(-1), astUtils.isClosingParenToken, ) : sourceCode.getTokenAfter(leftParen); return { leftParen, rightParen }; } case "ArrowFunctionExpression": { const firstToken = sourceCode.getFirstToken(node, { skip: node.async ? 1 : 0, }); if (!astUtils.isOpeningParenToken(firstToken)) { // If the ArrowFunctionExpression has a single param without parens, return null. return null; } const rightParen = node.params.length ? sourceCode.getTokenAfter( node.params.at(-1), astUtils.isClosingParenToken, ) : sourceCode.getTokenAfter(firstToken); return { leftParen: firstToken, rightParen, }; } case "ImportExpression": { const leftParen = sourceCode.getFirstToken(node, 1); const rightParen = sourceCode.getLastToken(node); return { leftParen, rightParen }; } default: throw new TypeError( `unexpected node with type ${node.type}`, ); } } //---------------------------------------------------------------------- // Public //---------------------------------------------------------------------- return { [[ "ArrowFunctionExpression", "CallExpression", "FunctionDeclaration", "FunctionExpression", "ImportExpression", "NewExpression", ]](node) { const parens = getParenTokens(node); let params; if (node.type === "ImportExpression") { params = [node.source]; } else if (astUtils.isFunction(node)) { params = node.params; } else { params = node.arguments; } if (parens) { validateParens(parens, params); if (multilineArgumentsOption) { validateArguments(parens, params); } } }, }; }, };